Hoisting apparatus



Oct. 9, 1951 W L 2,570,417

HOISTING APPARATUS Filed May 17, 1949 FIG.1

\ NTOR V AlbGrt WulLe ma )7 'ATTORN E'Y Patented Oct. 9, 1951 HOISTING APPARATUS Albert Wulleman, Le Canet-Marseille, France, assignor to Etablissments Paul Duelos Socit Anonyme, Le Canet-Marseille, France Application May-17, 1949, Serial No. 93,716 In France October 9, 1948 2 Claims.

It has already been proposed in hoisting apparatus comprising a swinging jib to vary the reach of the jib at a substantially constant level of the load by returning the hoisting cable from the jib-end sheave over a return-sheave so related in its movements with that of the jib that any variation in height of the jib-end sheave is accompanied by an equal variation in length, in an opposite direction, of the portion of the cable included between the jib-end sheave and passing over the return sheave.

My invention is concerned with an improved construction of hoisting apparatuses of this type. According to my invention the return sheave is supported by the jib and a second fixed sheave is provided, over which the cable issuing from the jib-end sheave passes before leading over the return sheave to the first mentioned fixed sheave. The assembly of those sheaves constitutes a pulley-block and provision is made for compensating any variation in length of cable from the jib-end sheave by a reverse variation in length of the cable portion between the jib-end sheave and said first mentioned fixed sheave over the pulley-block.

The features of the invention will appear from the ensuing description of a rotating ship-crane, embodying the improvements forming the subject of the invention and illustrated in the accompanying drawings, in which:

Figure 1 is a theoretical diagram of a device according to the invention;

Figure 2 is a simplified elevational view of a rotating ship-crane corresponding with the diagram of Fig. 1.

In the ensuing description, similar elements are designated by similar reference numerals.

As shown in the theoretical diagram of Fig. 1, the jib I of the crane is articulated about a horizontal axis at 2 and the whole structure may, when desired, be rotated bodily about the vertical axis 3. A cable 4, secured to the jib I and passing over a fixed sheave 5, makes it possible to vary the inclination of the jib and thereby the reach of the load. The hoisting cable 6, which, in describing the theory of operation, will be assumedconnected with the fixed point I, passes over a fixed return sheave 8, over a return sheave 9 carried by the jib, over a second fixed sheave Ill coaxial with the sheave 8, then over the sheave II of the jib-end and supports at its end the load I2.

When it is desired to reduce the reach of the crane, the jib is raised by swinging it about its articulation pivot 2, say from the position I illustrated in full lines, to the position Ia, shown in chain lines, and the sheave II is thus shifted to the higher position IIa. This may .be accomplished by pulling the hoisting cable 4. It will be seen that in this movement, the distance between the sheaves 9 and 8-10 is varied, the assembly of those sheaves in efiect constituting a pulley-block having one fixed end (sheaves 8 and I0) and the other end rigid with the jib (sheave 9).

In order that the elevation of the load should not vary, it is simply necessary that the shortening of the pulley-block should result in paying off the length of cable necessary to compensate for the variation in height of the jib-end sheave I I when shifted from the position I I to the position Ila. This may easily be obtained by suitably selecting the distance from the axes of sheaves 9 and 8Iil to the jib swinging axis 2.

Fig. 2 shows, in a simplified form, an example of the invention as applied to a rotating shipcrane.

The rotating pivot of the crane is constituted by a vertical post I3 the bottom part of which, included between the decks I4 and I5, rests on a stepped bearing 16 on the lower deck l4 and is guided by a roller-bearing annulus I1 in the upper deck I5. Above this deck the post may be small in height and carries at its top end the coaxial sheaves 8 and I6 forming the fixed end of the pulley-block, which takes up any variations in reach, and whose other end, formed by the sheave 9, is movable with the jib. The sheaves Band Ill could be otherwise than coaxial and occupy different positions along the post. The hoisting cable 6 is wound over the winch I8 carried on a platform I9 mounted on the roller-annulus H.

The jib is raised by means of a hydraulic jack 20 secured to the post beneath said platform and acting downwards on a movable pulley 2| over which the jib-raising cable 4 is passed between the fixed sheave 5 and a fixed point of attachment 22. It is seen that the action of said jack in lowering the pulley 2I causes the jib to be moved upwards and conversely retraction of the jack makes it possible to move the jib down to a horizontal position along the deck. There has been shown in chain lines, at I a and lb, an elevated position and a horizontal position of the jib and it will be seen that if the winch I8 remains fixed, the jib is made to shift from one to the other of those positions without any variation in the height of the load I2.

An advantage of the device described is that 3 it becomes possible to provide a rotating post small in height over the upper deck and therefore the bulk of the hoisting apparatus may be small when at rest, a particularly desirable point where a ship-crane is concerned.

The invention is of course in no way restricted to the exemplary embodiment illustrated and described, a similar device being applicable to any type of hoisting apparatus.

What I claim is:

1. A hoisting apparatus comprising in com bination, a frame, a jib swingingly connected at one end to said frame, a sheave at theopposite end of said jib, two fixed sheaves supported by said frame and spaced substantially above said one jib end, a movable return sheave rotatably mounted on said jib, a hoisting cable passing from said jib-end sheave over one of said fixed sheaves, then over said movable sheave and returned over the other of said fixed sheaves, so that any variation in length of cable from the jib-end sheave is accompanied by an equal and reverse variation in length of the cable portion between said jib-end sheave and the last said fixed sheave, hoisting means for said cable, and means for swinging said jib.

' 2. A hoisting apparatus comprising in combination, a frame having a rotating vertical post, a platform supported by said post and rotatable therewith, a jib swingingly connected at one end to said post above said platform, a sheave at 4 the opposite end of said jib, two fixed sheaves supported by said post and spaced substantially above said one jib end, a movable return sheave rotatably mounted on said jib, a hoisting cable passing from said jib-end sheave over one of said fixed sheaves, then over said movable sheave and returned over the other of said fixed sheaves, so

that any variation in length of cable from the jib-end sheave is accompanied by an equal and reverse variation in length of the cable portion between. said jib-end sheave and the last said fixed sheave, a winch on said platform for winding up said hoisting cable, a hydraulic jack secured to said post beneath said platform acting downwards on a movable pulley, a fixed sheave rotatably mounted on said post and spaced substantially above said one jib end, and a jib-raising cable attached by one end to said jack and by its other end to said jib and passing over said pulley, over the last said fixed sheave and attached tothe jib.

ALBERT WULLEMAN,

REFERENCES CITED FOREIGN PATENTS Country Date Great Britain Jan. '7, 1915 Number 

